@Dominions Son
Is the fluid medium of semen water based, or oil based?
My understanding is that it's mostly water, even though the protein content gives it a slimy feel.
At the stated density it's only marginally denser than water and may not be heavy enough to break the surface tension of the water.
I'm not sure surface tension is the only criterion. And even if it's able to surmount the surface tension, it might float anyway until the temperatures even out or the semen becomes to dilute to remain a discernible agglomeration.
I suspect there are so many variables in play that the only way to find out is by conducting practical tests.
To start, I need a dozen male (not trans male) volunteers who are prepared to forego ejaculation for 48 hours in the interests of science :-)
Seriously, I might experiment myself, but I feel it would be rather gross to divulge any results here.
AJ